Lamberts don't have a central meridian, they have a parallel of origin and two standard parallels. You can back-calculate the parallel of origin if there is a value printed on the chart as 'n' or the 'constant of the cone' or 'convergency factor'. This is the sine of the latitude of the parallel of origin. For instance, if it says n=0.866 it means sin latitude X = 0.866, therefore latitude X, the parallel of origin = 60º.
Central meridians are present on transverse Mercator charts such as the UK Ordinance Survey. It used to be that the half mill charts were Lamberts and the quarter mill charts transverse Mercators. I'm not sure if that is still the case but it should say on the chart.
[edited for spelling!]
Last edited by Alex Whittingham; 13th August 2004 at 15:08.